1. Field of the Invention
The present invention relates to a transfer apparatus and a transfer method for detecting a transfer state of a substrate, when mounting and transferring a semiconductor wafer, a glass substrate for flat panel display and other substrates thereon.
2. Description of the Related Art
Apparatuses for processing a substrate such as a semiconductor wafer (substrate processing apparatuses) include the one that transfers the substrate stored in a substrate waiting part to a substrate processing part. Methods of transferring the substrate to the substrate processing part include a method of mounting the substrate (transferred component) on a transfer arm (driven means) and moving the transfer arm by a driving force of a motor (driving means) to thereby transfer the substrate to a desired position. For example, a motor, a pulley, and a belt constitute a moving mechanism at least in the vertical direction and the horizontal direction, the pulley is rotated using the rotational driving force of the motor, and the belt wound around the rotating pulley is moved at least in the vertical direction and the horizontal direction to move the transfer arm coupled to the belt. Thereby, the substrate mounted on the transfer arm can be transferred to the desired position.
Japanese Laid-open Patent Publication No. 2011-42463 discloses, about a stacker vertically moving a tray by driving via the belt, a technique capable of detecting tooth skip of the belt from at least one of the variation in rotation speed of the motor and the position of the tray.